Hi there!
Over the past few weeks I've been wanting to transform a duffle bag into a boombox which I can bring along to parties and chill sessions with friends. It needs to be battery powered, which I plan on accomplishing by building a 18650 battery pack. The charging circuit shouldn't be that big of a problem since I do have some electrical engineering experience. I also have a spare power supply from a PC lying around (Corsair CX650M, 650W), which I can use to power the amplifiers.
We mostly listen to bass heavy music like house, hip-hop, techno. So the speaker should be tuned more towards the bass side.
Since size is limited to about 31cm in height, 49cm in length, and 29cm in width, I'm not too sure how to get the most amount of bass while also leaving room for the other speakers & electronics. I'm currently looking at the Dayton UM8-22 (8") as a subwoofer driver (which could potentially be swapped with a low-profile driver if space becomes too limited) paired with an ICEpower 300AS1 amplifier, which will handle up to 300W Rms.
I don't think a ported enclosure will fit so it'll have to be a sealed enclosure or with a passive radiator (which I don't know much about). The specifications of the driver mention a 0.35 cubic ft (about 10 liters) net internal space for a sealed enclosure, which should give a Qtc alignment of 0.8 (I don't know whether that will sound great for my application).
For mids I have picked the Dayton Audio PA130-8 (5"), because the reviews looked promising. I don't really know what I should look for in a mid-range speaker otherwise. The sensitivity also seems to line up pretty nicely with the subwoofer. I've picked a Dayton Audio DC28F-8 (1-1/8") as a tweeter.
I've not run any numbers through a simulation yet, since I don't know how to do so. I'm currently looking for advice for picking the correct drivers and help with designing the enclosure.
I think this would be a fun project. Looking forward to reading your suggestions!
Jerre
Over the past few weeks I've been wanting to transform a duffle bag into a boombox which I can bring along to parties and chill sessions with friends. It needs to be battery powered, which I plan on accomplishing by building a 18650 battery pack. The charging circuit shouldn't be that big of a problem since I do have some electrical engineering experience. I also have a spare power supply from a PC lying around (Corsair CX650M, 650W), which I can use to power the amplifiers.
We mostly listen to bass heavy music like house, hip-hop, techno. So the speaker should be tuned more towards the bass side.
Since size is limited to about 31cm in height, 49cm in length, and 29cm in width, I'm not too sure how to get the most amount of bass while also leaving room for the other speakers & electronics. I'm currently looking at the Dayton UM8-22 (8") as a subwoofer driver (which could potentially be swapped with a low-profile driver if space becomes too limited) paired with an ICEpower 300AS1 amplifier, which will handle up to 300W Rms.
I don't think a ported enclosure will fit so it'll have to be a sealed enclosure or with a passive radiator (which I don't know much about). The specifications of the driver mention a 0.35 cubic ft (about 10 liters) net internal space for a sealed enclosure, which should give a Qtc alignment of 0.8 (I don't know whether that will sound great for my application).
For mids I have picked the Dayton Audio PA130-8 (5"), because the reviews looked promising. I don't really know what I should look for in a mid-range speaker otherwise. The sensitivity also seems to line up pretty nicely with the subwoofer. I've picked a Dayton Audio DC28F-8 (1-1/8") as a tweeter.
I've not run any numbers through a simulation yet, since I don't know how to do so. I'm currently looking for advice for picking the correct drivers and help with designing the enclosure.
I think this would be a fun project. Looking forward to reading your suggestions!
Jerre
Jerre,
A sealed 8" will suck battery power quickly without producing much output.
The B&C10CL51 would be a good woofer choice for it's light weight and output potential, though won't go as low as the Dayton UM8-22, it would use less than 1/10th the power for the same output level at 60Hz, though also would use a larger box, still within your size restraints.
At 100 watts, the UM8-22 would put out around 101dB, the B&C10CL51 around 112dB.
A 10dB level difference sounds more than twice as loud, or at the same level would allow near 10 times more play time before re-charge.
This thread worked on a similar project:
https://www.diyaudio.com/community/threads/backpack-challenge.366187/
A sealed 8" will suck battery power quickly without producing much output.
The B&C10CL51 would be a good woofer choice for it's light weight and output potential, though won't go as low as the Dayton UM8-22, it would use less than 1/10th the power for the same output level at 60Hz, though also would use a larger box, still within your size restraints.
At 100 watts, the UM8-22 would put out around 101dB, the B&C10CL51 around 112dB.
A 10dB level difference sounds more than twice as loud, or at the same level would allow near 10 times more play time before re-charge.
This thread worked on a similar project:
https://www.diyaudio.com/community/threads/backpack-challenge.366187/
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Thank you for your reply!
The B&C 10CL51 looks good, thanks for the suggestion! Although I'm still a bit unsure about the enclosure design. Do I have to keep the subwoofer separated from the midrange-woofer and tweeter? Or is it OK if they're all in the same space. I've read that having the subwoofer in the same box that it could interfere with the midrange driver through the pressure waves. Also, what is your suggestion for the type of enclosure? Could a ported enclosure work within my size restraints?
Kind regards,
Jerre
The B&C 10CL51 looks good, thanks for the suggestion! Although I'm still a bit unsure about the enclosure design. Do I have to keep the subwoofer separated from the midrange-woofer and tweeter? Or is it OK if they're all in the same space. I've read that having the subwoofer in the same box that it could interfere with the midrange driver through the pressure waves. Also, what is your suggestion for the type of enclosure? Could a ported enclosure work within my size restraints?
Kind regards,
Jerre
I can answer the first question.
The PA130-8 has an open back and must be in its own internal enclosure so that it is isolated from the back pressure of the subwoofer.
The DC28F-8 has a closed back so does not require to be isolated from the subwoofer. It can occupy the same enclosure as the PA130-8 if you like.
The PA130-8 has an open back and must be in its own internal enclosure so that it is isolated from the back pressure of the subwoofer.
The DC28F-8 has a closed back so does not require to be isolated from the subwoofer. It can occupy the same enclosure as the PA130-8 if you like.
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Ah, great. Thanks for the info.
I'm not looking to buying an off-the-shelf unit. I did know they exist but I'm planning on adding my own features to the box like lighting, mobile chargers, etc. 🙂
A ported cabinet will work with your size restraints.
After excluding the volume taken up in the interior box required for the midrange driver, volume of the woofer, the port, and 1/2" cabinet wood and bracing, 31cm x 49cm x 29cm should leave around 26 liters net volume.
A port with an area of 120cm2, 30cm long should give around 59Hz Fb (box tuning).
With 36volt input, about 200 watts into the 6.6 impedance minima, excursion just reaches the B&C10CL51 Xmax of 6mm above Fb. Ideally, a HP (high pass/low cut) filter would be used at around 50Hz to keep low frequency excursion (speaker flapping) under control and useless power wasting.
The B&C10CL51 Xlim is around 12mm, suspension limited, in real life the speaker will never have the excursion below Fb that this Hornresp simulation predicts.
Art